1. Field of the Invention
The present invention relates to a removable fin system, and in particularly to removable fin system for an aquafoil, such as surfboards, body boards, wave skis, sail boards, wake boards and the like.
2. Background and Prior Art
It is known to produce a releasable fin for surfboards and the like, such that the fin can be replaced if damaged, or conditions of the water changes, e.g. different wave conditions. In the prior art, such as Australian patent no. 665804, some of the replaceable fins are affixed to the boards by screws, which requires tools to remove and replace the fin, or by a cam, as in Australian patent 718340. In other situations the replaceable fins have a tab, which fits into a slot cut into the board and has backwardly facing barbed sides, which lock into the core of the board to resist removal.
Another prior art replaceable fin is shown in Australian Patent no. 693962, in which the replaceable fin system has a pot fitted into the board. The pot has a central slot with reversed tapered walls flaring from its opening to its base within the board. The fin has a tab portion to fit into the central slot. The tab has tapered sides, complementary to the flared central slot, which at least one vertically longitudinally extending cutout in the tab to form wings, which are forced together to allow the tab to fit within the slot opening.
Whilst this system is acceptable, it has been found that the reverse taper on the wings of the tab, allows the tab to wiggle partway out of the slot in certain conditions of high stress, which greatly reduces the efficiency of the fin.